Research and development of the present invention and application have not been Federally-sponsored, and no rights are given under any Federal program.
1. Field of the Invention
This invention relates to closures for containers or A enclosures, and more particularly to closures of the type employing threaded means to ensure the tightness and seal of the closure.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97-1.99
Various types of threaded closures have been proposed and utilized in the past. These closures have in general employed thread-like cooperable means to effectuate a tight seal. In some instances the thread-like means was single-acting in effect, as in the nature of buttress threads. In other cases, the thread-like means had sharp crests or else rounded crests, depending on the desired circumstances.
More specifically, the present invention relates to thread formations carried by closure members of different diameters by which various forces and leverages may be applied to the closure body either by hand or with a tool to obtain specific different results.
In U.S. Pat. No. 882,877 a closure is provided for use as a deck plate, such closure having spring-loaded detent pins xe2x80x9cPxe2x80x9d to yieldably hold the plate in any of various rotative positions. No positive screw-action locking is disclosed or contemplated.
U.S. Pat. No. 849,618 shows a deck plate having a flush lever type lock which when lifted releases the closure 8 for removal. This patent also does not disclose a screw-type locking action. Release is effected by the same movement which is used to lift the closure out of its sealing position.
In the Ely Pat. No. 829,862 a slide bolt 6 is spring charged to locking position and can be retracted by sliding the release knob 9 to the right as viewed in Sectional view FIG. 4.
U.S. Pat. No. 304,684 issued to Adams is poorly gotten up. Presumably there are cam surfaces (marked in pencil) which operate dogs xe2x80x98b4xe2x80x99 to effect the release. No screw action occurs but in general it is dissimilar to the general trend of deck plates found in a search of the art.
In Webster Pat. No. 1,125,229 a filler tube cap in the form of a screw is disclosed. Projections 36 act as finger-engageable grips to enable gripping of the closure body for turning it to either closed or open position.
U.S. Pat. No. 3,707,241 features an internally threaded closure d and a reinforcing means for strengthening and backing the mouth portion of the container. This is applied especially in connection with thin-walled containers.
Of more particular interest is U.S. Pat. No. 4,246,859 which reveals a boat deck cover which is similar in many respects to the cover which is the subject of the present invention. The cover plate construction of the patent reveals cooperable buttress threads 28 and 30 having special dimensions to provide a certain amount of slop between them. No other special features are provided on the cover plate for facilitating either the loosening action or the tightening action of the plate. A resilient sealing washer 46 is carried by the stationary fitting of the closure assemblage to effect the seal. However, such arrangement has drawbacks since the washer is subject to being scruffled and damaged, thereby adversely affecting the seal.
In U.S. Pat. No. 4,280,434 a cover plate construction is provided which cooperates with a resilient washer also on the deck fitting, to obtain a seal. The object is to compensate for fluctuations or variations of the cover plate and eliminate strain or warping effects that might occur should the cover plate become malformed.
Very often closures are found to be more difficult to open than to close. In some cases this turns out to be of distinct disadvantage, especially where a proper opening tool is not available. To cope with this, various types of wrenches can be employed in conjunction with prior closures in order to secure easy opening movements.
The above pointed-out drawback and disadvantages of prior screw operated seals are obviated by the present invention, which has for one object the provision of an improved easily closable and also easily openable closure or sealing plate of the screw variety, which can, if desired, be readily economically fabricated of durable plastic substance or other material in a configuration that is adaptable to either hand or tool operation and is also especially rugged, being capable of an extended long life.
Another object of the invention is to provide an improved screw-type cover plate for sealing an opening as above set forth, which is easily operated in various modes as to its being tightened and loosened.
A further object of the invention is to provide an improved thread-type closure as characterized which has different capabilities with respect to the opening and closing forces that are needed. In some circumstances a relatively small releasing or turning force is sufficient to remove the closure body.
A still further object of the invention is to provide an improved thread-type closure as above described, which can remain flush with the surface to which it is attached when in a sealing position.
An additional object of the invention is the provision of an improved screw-type cover plate as above characterized, which can be very economically molded of plastic substances, and yet remain strong and durable for the purposes desired.
Yet another object of the invention is to provide an improved threaded closure of the type indicated, wherein great forces can be exerted thereon as by an operating wrench, due to the shaping and disposition of shoulders or recesses in the closure body, and by the configuration of the recess walls thereof.
A feature of the invention resides in the directional function of the opening and closing means or recesses to favor either opening or closing of the access plate, as the case may be.
An important feature of the invention is that the placement of the opening and closing finger or wrench holes provides a lower but sufficient amount of torque to close the cover utilizing the innermost grips, and a higher degree of torque to open the cover by utilizing the outermost grips. Also that the outermost, opening finger grips are unidirectional in that they are designed to slip at minimum resistance, so that they are not useful to close the cover at the higher torque level.
Another feature of the invention resides in the simplicity of the structures involved in achieving the above results.
Other features and advantages will hereinafter appear.